Method of making poppet valves



Sept. 9, 1952 T, PERKES 2,610,279

METHOD OF MAKING POPPET VALVES Filed March 17, 1949 Fred J? Pep/65 Patented Sept. 9, 1952 METHOD OF MAKING POPPET VALVES Fred T. Perkes, Willoughby, Ohio, assignor to Thompson Products Inc., Cleveland, Ohio, a

corporation of Ohio Application March 17, 1949, Serial No. 81,987

3 Claims.

The present invention relates to a method of.

making a poppet valve and more particularly to an improved method for welding a tip end on the stem of a hollow poppet valve containing a body of coolant.

Coolant-filled poppet valves have heretofore been sealed with Welded or stem plugs or head caps or have been composed of separate stem and head portions joined with ,a sealing weld. However, the head cap welds and the head and stem joining welds are in areas of the poppet valve that must be exposed to combustion gases and are subject to corrosion, high temperatures and Wear conditions that do not exist at the tip end of the valve stem. On the other hand while the heretofore used stem plug welds were out of the combustion zone they had to be covered with hard tip ends to resist tappet action thereby necessitating another welding operation. It was not heretofore practical to simultaneously seal and tip the valve stem because welding flash would oxidize or ignite inflammable valve coolants such as sodium and a confined weld area could not be obtained.

The present invention now provides a simple, inexpensive method of simultaneously sealing and tipping a coolant-filled poppet valve which may be carried out entirely by the use of automatic welding machinery. The method not only positions the sealing weld outside of the hot corroding zone of poppet valve operation but confines the weld and flash to a small zone spared from the coolant. Further, the welded on tip. can be of sufficient length to form the valve spring retainer groove area of the stem.

The method of the present invention comprises generally the attachment of a hard valve tip to the open end of a hollow valve stem depending from the valve head. The valve stem and tip are preferably formed of different metals, usually steel alloys, with the tip being formed of a harder material for receiving the valve-actuating mechanism. One of the mating faces of either the valve stem or the stem tip is beveled. Preferably, the exposed valve stem end, which is, annular in cross-sectional configuration, is beveled, the bevel angle preferably being from 5 to from a plane normal to the axis of the valve stem. The valve tip is preferably formed of cylindrical stock of substantially the same outside diameter as the valve stem, one end face of the valve tip having a cylindrical recess formed therein of substantially the same diameter as the stem bore.

The beveled valve stem face and the recessed tip face are brought into abutment and an electric heating current is passed through the abutting faces. The heating current is maintained while the abutting faces are held in contact until the softening points of the faces are reached. When the softening points are reached, the abutting faces are jammed into tighter contact to foreshorten the combined length of the tip and the stem with the formation of a permanent welded bond between the abutting faces.

The recess formed in the tip allows equal flowing of the weld flash to assure a consistently strong weld. The beveled face, which may be formed on either the tip face or the corresponding stem face, is eifective to create'a high resistance area to start the flashing. The bevel angle is such that there is an equal upsetting of the weld area upon the jamming of the faces together to cause a strong weld while the upset length and the flash-off length are controlled by the tube wall thickness. Further, the quickness of the welding operation, when carried out in automatic welding machinery, is such that sodium contained within the head portion of the valve, and thus spaced from the welding zone, does not melt or vaporize during the welding operation.

It is, therefore, an important object of the present invention to provide an improved method of making a coolant-filled poppet valve.

Another important object of the present invention is to provide anim roved apparatus for welding a tip end on the stem of a hollow poppet valve containing a body of coolant.

A further important object of the present invention is to provide animproved coolant-filled poppet valve having a tip end welded to the hollow valve stem, the tip end being out of the combustion zone of an engine in which the valve is disposed and the valve tip being of hardened material to resist tanpet action.

A still further object of the present invention is to provide an improved method of making a coolant-filled poppet valve by the welding of a tip end to the hollow valve stem by the use of automatic welding machinery.

Other and further obiects of the invention will be apparent to those skilled in the art from the following detailed description of the annexed sheet of drawings which, by way of a preferred example only, illustrates one embodiment of the invention.

On the drawings:

Figure l is a side elevational view, with parts broken away, of a coolant-filled poppet valve 3 made in accordance with the method of the present invention;

Figure 2 is a view of the valve head and stem prior to the welding operation;

Figure 3 is a cross-sectional view of the valve tip prior to the welding operation; and

Figure 51 a diagrammatic view; of apparatus oapablebf carrying out'the method bf thelpresht invention and showing the valve and tip end in vertical cross-section.

As shownon the drawings: I W I In Figure l, the reference numeral refers generally to a coolant-filled poppetvalve mader in accordance with the me't-hdic ifjofgthegp, sntf invention and including a valve head portion H, a hollow valve stem portion I 2 formed integrally with the valve head ll and'having' 'afiriterior axial bore I3 and a valve tip portion l4 welded to the valve stem. The bore I3 is partially filled it co ant am al firri re a ne le k gig" 15 1 "age ma'cfiiiiedand ground into the tip '5'?? this n 11656-.- vi I.

.3. 1.257215 .03'-Ma"ximum Uri... .03 Maximum 19.-23. l.0ll*2.fl0 Iron g Balance "The; valve stem tip- I 4 isrpreferably termed; of alharder. alloylsteel having. wear characte rlstics 6 and "strengthsuitable iiorethis usen .I have round thl following .alloy' to. be particularly desirable bf 'll nrm na het pl' Percent by Ingredients Weight-v.

lie u: r.r lrl.- l an. :If

Garb .3s-,43 Manganese r ..r .70.90 ili n i :20-:35 Ifhmphnrh .QfK Maximum Biilphurlrr. v .04 Maximum Chromiu -.5 5,-i25 Ni Pl 1.10:1:40 Iron I) Balance a ree it rw camarad r e is illustrate in gure 21min in which it may be eir ma lneiq ep numetlsiorv r t i beveled asat l6, beveled face'biiiganriular i V on'rig'u ation' and'ektndifiguniformly about tii'piiphei bf-"thfendrace |5. Thfa'rig'l'e 'be-' & tween beveled face l6{ahdTaradialplane interd secting'"th'end"face preferably'froni 5 to 10 for reasons-to be: hereinaftermore fully described. shownin vFigure 3, the stem tip 14 is of sub-. stantially the. same. outside-diameter? as the stem l2 and is provided With-Hfiatrend. facel] and, a '5 cylindrical recesstorwell I 8 isdrilled into this end facemsThelreeess 481s d g-s stan i l y th Same diameter e xi l here. 1- ist m l2; r If DQ 511 5 lt qv l d 1 l1 m r. ve ed i a la e: of theb el denit li a Qt-14th? eiem- Thus, a beveled face l6 may be provided on either one of the members as desired. t g g,

i suitable apparatus for weldin'g the-tip M to the valve stem l2lisfi liistratedjingri u e pi the 1 drawings; The apparatus 'is "indicated errerany by reference numeral 20 and includes a pair of upper clamping arms 2| and 22 carrying upper electrode sections 23a and 24a, respectively. Lower mating electrodes 23b and 241) are provided to coact with the upper sections. Each section carries an alloy insert chuck section to providel opposed chucks. 2 5; and 2-6 which have gripping bores 25g, andfg li'dltoi hold'anjinserted rod therein when the clamping arms are closed.

The electrodes 23a and 23b are laterally shiftable, the section 23b bein secured to a stationary pfaIten TFwhile'Tthe electrode section 24b is secured to a movable platen 28 which, in turn, is

cari' -iedbyfa generally U-shaped laminated repletes theperipliery the surfaces 15 "and I 1 are placed in abutment y movement,orthe movabljp ,2 8. caused by rcnmg ice'ntact hf "the" roller" 33 with the flash-off surface 35 of theicamca l. e

It will readily be uii drsto'odfby those skilled in; the 7 art that ,upon the passage. of current through the "member l2 ant 1514 wh'il el held abu tmnt'jthe surfaces; l5 and l 'lf-aieg'heated';

"I he' current nowingjpet en electrode sections is lsof'rgulatedthait t fir f'ac-es 71.5 and. IT freacl'itheir" annealing or soft n g temperatures dur-t mg that tini' mter ai dufing'. which cani' roller 33 contacts the 'ifla'sh surf-ace 35 of cam 34; Upon contact betweeh rolleriii and t e upsettin cam "surface 36, the abutting surfaces I l 5, and i l'lv will 'be jammed into T contact under a, relatively pres ure the upsetting; plateau 37. will may be! .removed' from' the chucks 25 and 26; either manually byinterrup'ting movement of the flash-off cam vor'.ajutr'n'natically, as}desired! I,

.'For best resi'iltsithas" been foundl l sirable to,

. have the coun portion l8 extend iintotip from 5 to is highly desirable in order that there may be an equal upsetting of the weld area to form a strong weld.

When the valve stem 1! is mounted in the chuck 25 its beveled end is positioned to project beyond the chuck a distance approximately twice the distance that the end face I7 is spaced from the chuck 25. This differential overhan of the mating faces from the chucks is desirable to insure the same temperature at each weld end due to the differences in material employed for these two elements [2 and It.

It is desirable to correlate the upset length, determined by the rise of cam surface 36, and the flashing time determined by the length of time the cam surface 35 contacts the cam roller 33, with the tube wall thickness. The correlation between these variables is shown in the accompanying Table A, in which T is the tube wall thickness; B is total material lost; D is total flash-off; H is total upset; J is material lost per piece and O. D. is outside diameter of tubing:

As a particular example, in employing tubular stock of 0.238 inch outside diameter having a wall thickness of 0.090 inch, the upset on each section of the valve is approximately of the order of 0.062 inch, while the burn-away or fore-shorten ing of the combined length of the tip and valve stem is of the order of 0.176 inch for each of the valve parts. It will also be understood that the flash length of the cam surface, i. e., cam surface '35, should be correlated with the annealing point or softening point of the alloys employed. For example, alloy composition #1, hereinbefore disclosed, is suitable for use in forming the valve :head and stem portion, has a softening point of approximately 1,600 F., while the annealing point of alloy composition #2 is approximately 1,300 F.

In the formation of coolant-filled valves, it is possible to employ the present method with such low melting coolants as sodium, inasmuch as the valve head and stem are normally filled up to from 50 to 60% of total volume with sodium, and since the sodium is in the solid state at room temperature and is located at the head end of the valve away from the welding zone. Thus, the sodium does not have an opportunity to melt or vaporize, due to the quickness of the welding operation hereinbefore described.

It will, of course, be understood that various details of the method and apparatus may be varied through a wide range without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

I claim as my invention:

1. The method of simultaneously sealing and tipping a coolant-containing poppet valve having a hollow valve stem open at the tip end which comprises beveling the open end of said stem, inserting coolant in the stern through the beveled open end thereof, spacing the coolant from the open end of the stem, recessing one end of a hard metal tip to provide an annular end face thereon, contacting the beveled end of said stem with the said annular end face of said tip, passing an electric heating current through said contacting end and end face to rapidly bring said end and end face to their respective softening points without substantially heating the coolant in the valve, and jamming said end and said end face together after their respective softening points have been reached to firmly bond said tip to said stern in a welded joint.

2. The method of simultaneously sealing and tipping a coolant-filled poppet valve by welding a hardened closure tip to the top tip end of the valve stem which comprises beveling said open tip end of said stem at an angle ranging from 5 to 10, substantially filling said stem with a solid inflammable coolant capable of becoming liquid at engine-operating temperatures, drilling an axial aperture of substantially the same size as the bore of the valve stem in a rod of hard valve tip metal, contacting the beveled stem end with the aperture end of said rod, and flash buttwelding said rod to said stern while exerting pressure thereon, the spaced relation of said buttwelding area from said coolant preventing ignition of said coolant.

3. A hollow coolant-filled poppet valve comprising a valve head, a hollow valve stem depending from said head and containing a body of coolant, and a hardened valve stem tip closing the end of said stem, said tip and said stem having mating beveled terminal faces in flash buttwelded together relation, said faces being in spaced relationship to said coolant and the welded zone being sufficiently remote from said valve head to be out of contact with combustion gases flowing around the valve in an engine operating with the valve.

FRED T. PERKES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,294,416 Dady Feb. 18, 1919 1,468,927 Spire Sept. 25, 1923 1,796,345 Powell Mar. 17, 1931 1,916,012 Otto et al. June 27, 1933 1,916,013 Otto et al June 27, 1933 1,971,369 Coryell Aug. 28, 1934 2,085,583 Hanson June 29, 1937 2,280,758 Voorhies Apr. 21, 1942 2,293,523 Warren Aug. 18, 1942 2,394,177 Hoern Feb. 5, 1946 2,440,461 Clements Apr. 27, 1948 2,471,937 Colwell May 31, 1949 

